From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D15502E6CA6; Fri, 20 Mar 2026 21:08:23 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774040903; cv=none; b=MWqzcwCdDjslScYWKaAlCWYg4FbD9dIIOt9fumyJ6ez9Nyx/qzSZY1TJ6QoELSLc6c5TzW3cRADfKyWblFw4kYPxPulpElks+xlbnFD+tMGp5gSVGgYYJpud5MIZ7ugHhcJ7uUuN15FPcfHaXJqiFVhXMx+HaPdXqGNcoXkcFvI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774040903; c=relaxed/simple; bh=u0zdmPIhkicnjjaekGwGuaSnl24uNp/SD6pTY4tTyoI=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=A6BGGSrG9/BXqjmalSf6WATIL+CQggZXnY21NICBtZQMVgEkjwS0XfV1dwIyqImk88F64N9FVvs6I18BaV7BesdGk9hbkkENtKZAxY8ogWwOvZR5dydhF7Q/lpvpb74U9c4bSEE/KOseskDU3YbDc5AzAQH+aIGwQ8F01OJwpMw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=qC8HBmDJ; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="qC8HBmDJ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 84E28C4CEF7; Fri, 20 Mar 2026 21:08:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1774040903; bh=u0zdmPIhkicnjjaekGwGuaSnl24uNp/SD6pTY4tTyoI=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=qC8HBmDJbc3QTlANvhaLjcn0O5ay5GqzDEvYHXsOkZQejTAbOkx+bkEo+ki3/IcqS 2zxeTAiPAA/ZnIrs1vWkKIH1qQM6hWWWHXeyTtkY/GTcJVwCwrNv3c5QnInC7yBUEZ Emq3X5gGUqXLf66MStAVqC5m2WCTfSbnlpAHXDlhTtb1Ap6h4AtLg1EuCVIYnM3U2k 9XYMGV8lFcVQ3Ofo63x/aFk8UD8Gt0FgB8ThIniVMGJGtCnjMclwn9hpHtv2VORGXx vrpZQBmOIITR6wCUusRaEbZoc8REFtZupMT7Shny3yqCThx6DNBFOpK9/XXBVuE7o9 ZHBuzLHK9WgAw== Date: Fri, 20 Mar 2026 14:08:12 -0700 From: Nathan Chancellor To: "Lorenzo Stoakes (Oracle)" Cc: Andrew Morton , Jonathan Corbet , Clemens Ladisch , Arnd Bergmann , Greg Kroah-Hartman , "K . Y . Srinivasan" , Haiyang Zhang , Wei Liu , Dexuan Cui , Long Li , Alexander Shishkin , Maxime Coquelin , Alexandre Torgue , Miquel Raynal , Richard Weinberger , Vignesh Raghavendra , Bodo Stroesser , "Martin K . Petersen" , David Howells , Marc Dionne , Alexander Viro , Christian Brauner , Jan Kara , David Hildenbrand , "Liam R . Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Jann Horn , Pedro Falcato , linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-hyperv@vger.kernel.org, linux-stm32@st-md-mailman.stormreply.com, linux-arm-kernel@lists.infradead.org, linux-mtd@lists.infradead.org, linux-staging@lists.linux.dev, linux-scsi@vger.kernel.org, target-devel@vger.kernel.org, linux-afs@lists.infradead.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, Ryan Roberts Subject: Re: [PATCH v3 15/16] mm: add mmap_action_map_kernel_pages[_full]() Message-ID: <20260320210812.GA3988975@ax162> References: <54ff3670662e10a66ce0c1a13c0ae93b99a5f201.1773944114.git.ljs@kernel.org> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <54ff3670662e10a66ce0c1a13c0ae93b99a5f201.1773944114.git.ljs@kernel.org> Hi Lorenzo, On Thu, Mar 19, 2026 at 06:23:39PM +0000, Lorenzo Stoakes (Oracle) wrote: > A user can invoke mmap_action_map_kernel_pages() to specify that the > mapping should map kernel pages starting from desc->start of a specified > number of pages specified in an array. > > In order to implement this, adjust mmap_action_prepare() to be able to > return an error code, as it makes sense to assert that the specified > parameters are valid as quickly as possible as well as updating the VMA > flags to include VMA_MIXEDMAP_BIT as necessary. > > This provides an mmap_prepare equivalent of vm_insert_pages(). We > additionally update the existing vm_insert_pages() code to use > range_in_vma() and add a new range_in_vma_desc() helper function for the > mmap_prepare case, sharing the code between the two in range_is_subset(). > > We add both mmap_action_map_kernel_pages() and > mmap_action_map_kernel_pages_full() to allow for both partial and full VMA > mappings. > > We update the documentation to reflect the new features. > > Finally, we update the VMA tests accordingly to reflect the changes. > > Reviewed-by: Suren Baghdasaryan > Signed-off-by: Lorenzo Stoakes (Oracle) ... > diff --git a/mm/util.c b/mm/util.c > index 8cf59267a9ac..682d0d24e1c6 100644 > --- a/mm/util.c > +++ b/mm/util.c > @@ -1446,6 +1446,8 @@ int mmap_action_prepare(struct vm_area_desc *desc) > return io_remap_pfn_range_prepare(desc); > case MMAP_SIMPLE_IO_REMAP: > return simple_ioremap_prepare(desc); > + case MMAP_MAP_KERNEL_PAGES: > + return map_kernel_pages_prepare(desc); > } > > WARN_ON_ONCE(1); > @@ -1476,6 +1478,9 @@ int mmap_action_complete(struct vm_area_struct *vma, > case MMAP_REMAP_PFN: > err = remap_pfn_range_complete(vma, action); > break; > + case MMAP_MAP_KERNEL_PAGES: > + err = map_kernel_pages_complete(vma, action); > + break; > case MMAP_IO_REMAP_PFN: > case MMAP_SIMPLE_IO_REMAP: > /* Should have been delegated. */ > @@ -1497,6 +1502,7 @@ int mmap_action_prepare(struct vm_area_desc *desc) > case MMAP_REMAP_PFN: > case MMAP_IO_REMAP_PFN: > case MMAP_SIMPLE_IO_REMAP: > + case MMAP_MAP_KERNEL_PAGES: > WARN_ON_ONCE(1); /* nommu cannot handle these. */ > break; > } Not sure if it has been reported/addressed yet but it looks like mmap_action_complete() was missed here, as pointed out by clang: $ make -skj"$(nproc)" ARCH=arm LLVM=1 mrproper allnoconfig mm/util.o mm/util.c:1520:10: warning: enumeration value 'MMAP_MAP_KERNEL_PAGES' not handled in switch [-Wswitch] 1520 | switch (action->type) { | ^~~~~~~~~~~~ I assume diff --git a/mm/util.c b/mm/util.c index 682d0d24e1c6..c41c119a5a74 100644 --- a/mm/util.c +++ b/mm/util.c @@ -1523,6 +1523,7 @@ int mmap_action_complete(struct vm_area_struct *vma, case MMAP_REMAP_PFN: case MMAP_IO_REMAP_PFN: case MMAP_SIMPLE_IO_REMAP: + case MMAP_MAP_KERNEL_PAGES: WARN_ON_ONCE(1); /* nommu cannot handle this. */ err = -EINVAL; -- should be the fix? Cheers, Nathan